000
AXPZ20 KNHC 200926
TWDEP 

TROPICAL WEATHER DISCUSSION                                    
NWS NATIONAL HURRICANE CENTER MIAMI FL                         
1005 UTC SAT DEC 20 2014

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
           
THE MONSOON TROUGH AXIS EXTENDS FROM 05N77W TO 10N86W TO 09N89W. 
THE ITCZ AXIS EXTENDS FROM 09N89W TO 08N97W THEN RESUMES FROM 
07N103W TO 05N130W TO 05N140W. SCATTERED MODERATE AND ISOLATED 
STRONG CONVECTION IS WITHIN 75 NM EITHER SIDE OF THE AXIS 
BETWEEN 79W AND 82W. SCATTERED MODERATE CONVECTION IS WITHIN 75 
NM N OF THE AXIS BETWEEN 116W AND 119W.

...DISCUSSION...                                                 

HIGH PRESSURE AT 1025 MB NEAR 27N125W EXTENDS A RIDGE TO THE SE 
NEAR 15N110W. THE PRESSURE GRADIENT BETWEEN THE RIDGING AND 
LOWER PRESSURES ALONG THE ITCZ IS TIGHT ENOUGH TO SUPPORT FRESH 
TO STRONG TRADES ACROSS THE W CENTRAL WATERS WHICH WILL PERSIST 
THROUGH 48 HOURS...EXPANDING SLIGHTLY IN COVERAGE AS THE 
GRADIENT CONTINUES TO TIGHTEN. 

MEANWHILE LARGE NW SWELL UP TO 18 FT IS MOVING IN BEHIND THE 
REMNANTS OF A COLD FRONT WHICH ARE SCRAPING ACROSS THE WATERS  
FROM JUST W OF THE CALIFORNIA CHANNEL ISLANDS INTO THE N CENTRAL 
WATERS. A RECENT NEARBY ALTIMETER PASS SHOWING SEAS UP TO 15 FT 
AND A FEW SHIP REPORTS UP TO 13 FT. AN OLD SET OF NW SWELL IS 
MIXING WITH NE WIND WAVES GENERATED BY THE TRADES MENTIONED 
ABOVE AND COMBINED SEAS OF 8 FT OR GREATER COVER THE MAJORITY  
OF THE WATERS W OF 110W. MAXIMUM SEAS WILL SUBSIDE TO 13 FT BY 
48 HOURS.

THIS LONG PERIOD NW SWELL WILL ARRIVE ALONG THE PACIFIC COAST OF 
THE BAJA PENINSULA IN THE FORM OF 8-13 FT SEAS THIS AFTERNOON 
WITH 7-10 FT SEAS EXPECTED ALONG THE ENTIRE PACIFIC COAST OF THE 
BAJA PENINSULA ON SUN. THE SWELLS WILL SUBSIDE WITH 6-8 FT 
CONDITIONS EXPECTED ALONG THE ENTIRE PACIFIC COAST OF THE BAJA 
PENINSULA ON MON AND MON NIGHT...THEN SUBSIDING TO 4-6 FT ON TUE 
ACROSS THE COASTAL WATERS S OF 28N.

SATELLITE IMAGERY AND SCATTEROMETER DATA SHOW A WEAK 1011 MB LOW 
PRESSURE AREA EMBEDDED IN THE ITCZ NEAR 08N100W MOVING W AROUND 
10 KT. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
WITHIN 120 NM IN THE NW SEMICIRCLE OF THE LOW WHILE SEAS ARE 8-9 
FT WITHIN 180 NM OF THE LOW CENTER. THE LOW IS FORECAST TO REACH 
NEAR 08.5N110W AT 1011 MB BY 48 HOURS WHILE THE ASSOCIATED SEAS 
MERGE WITH THE AREA OF NW SWELL MENTIONED ABOVE.

GULF OF CALIFORNIA...RECENT ASCAT AND RAPIDSCAT SCATTEROMETER 
PASSES INDICATED 20-25 KT NW-N WINDS IN THE GULF FROM 23N TO 28N 
W OF 108W...WITH 15-20 KT ELSEWHERE. WINDS WILL DIMINISH TO 15-
20 KT LATER TODAY...FURTHER DIMINISHING TO 10-15 KT MON. MODEL 
GUIDANCE INDICATES WINDS INCREASING TO 20-30 KT N OF 26N W OF 
110W TUE...PERSISTING FOR ABOUT 24 HOURS.

GULF OF TEHUANTEPEC...A MAXIMUM OF 10-15 KT NOCTURNAL DRAINAGE 
FLOW IS OCCURRING TONIGHT INTO THE EARLY MORNING HOURS... 
INCREASING TO 20-25 KT SAT NIGHT INTO EARLY SUN...THEN BACK TO 
10-15 KT SUN NIGHT INTO EARLY MON. MODEL GUIDANCE CONTINUES TO  
SUGGEST THE THE NEXT GALE EVENT WILL BEGIN AROUND SUNRISE ON  
WED INCREASING TO NEAR STORM STRENGTH ON WED NIGHT.
  
GULF OF PAPAGAYO...NE 15-20 KT NOCTURNAL PULSES EXPECTED  
THROUGH EARLY MON...THEN ONLY 10-15 KT DRAINAGE FLOW EARLY 
TUE...THE BECOMING LIGHT AND VARIABLE WED.

$$
LEWITSKY